The XSetWMIconName convenience function
calls XSetTextProperty to set the WM_ICON_NAME property.

The XGetWMIconName
convenience function calls XGetTextProperty to obtain the WM_ICON_NAME
property. It returns a nonzero status on success; otherwise, it returns
a zero status.

The XSetIconName function sets the name to be displayed
in a window's icon.

XSetIconName can generate BadAlloc and BadWindow
errors.

The XGetIconName function returns the name to be displayed in
the specified window's icon. If it succeeds, it returns a nonzero status;
otherwise, if no icon name has been set for the window, it returns zero.
If you never assigned a name to the window, XGetIconName sets icon_name_return
to NULL. If the data returned by the server is in the Latin Portable Character
Encoding, then the returned string is in the Host Portable Character Encoding.
Otherwise, the result is implementation-dependent. When finished with it,
a client must free the icon name string using XFree.